CN112519513B

CN112519513B - Heavy duty pneumatic tire and method for manufacturing the same

Info

Publication number: CN112519513B
Application number: CN202010967687.1A
Authority: CN
Inventors: 金谷资辉
Original assignee: Sumitomo Rubber Industries Ltd
Current assignee: Sumitomo Rubber Industries Ltd
Priority date: 2019-09-18
Filing date: 2020-09-15
Publication date: 2024-02-13
Anticipated expiration: 2040-09-15
Also published as: JP2021046057A; CN112519513A; JP7379979B2

Abstract

The present invention provides a heavy duty pneumatic tire (2) which takes into account the influence on the durability of a bead portion (B) and achieves a reduction in the risk of damage to an RFID tag (78). The tire (2) has a tag structure (28) composed of an RFID tag (78) and a cover rubber (80) covering the RFID tag (78). The tag structure (28) is in contact with the outer apex (40 s) of the bead (8) from the outer side of the outer apex (40 s). An RFID tag (78) is located radially between the outer end (62) of the fiber reinforcement layer (20) and the end (54) of the folded portion (52) of the carcass (10). The ratio of the complex elastic modulus of the cover rubber (80) to the complex elastic modulus of the outer triangular glue (40 s) is between 0.7 and 1.5.

Description

Heavy duty pneumatic tire and method for manufacturing the same

Technical Field

The present invention relates to a pneumatic tire for heavy load and a method for manufacturing the same.

Background

In order to manage data such as manufacturing management of tires, customer information, and running history, it is proposed to incorporate an RFID (Radio Frequency Identification (radio frequency identification)) tag in a tire. Accordingly, various studies have been made on a technique of incorporating an RFID tag in a tire (for example, patent document 1 below).

Prior art literature

Patent literature

Patent document 1 Japanese patent laid-open publication No. 2015-223918

Disclosure of Invention

Problems to be solved by the invention

In a pneumatic tire for heavy load mounted on a vehicle such as a truck or a bus, an RFID tag may be disposed at a bead portion rather than at a side portion in consideration of damage caused by a trauma. In this case, in order to prevent damage to the RFID tag caused by deformation, it has been studied to dispose the RFID tag at a position where the deformation is small after covering the RFID tag with a soft rubber.

However, the hard chafer adjacent to the inside apex is located around the location where the deformation of the RFID tag is less in the predetermined arrangement. Therefore, if the RFID is disposed at a position where the deformation is small, the risk of damage may be increased due to the chafer pressing the RFID tag. Soft rubber is difficult to prevent damage to the RFID tag caused by the pressing of the chafer.

In order to reduce the risk of damage to the RFID tag, for example, if the RFID tag is covered with hard rubber, deformation may be concentrated at the end of the folded portion, and durability of the bead portion may be reduced.

The present invention has been made in view of such a practical situation, and an object of the present invention is to provide a heavy-duty pneumatic tire in which the influence on the durability of a bead portion is considered and the risk of damage to an RFID tag is reduced.

Solution for solving the problem

A heavy-duty pneumatic tire according to an embodiment of the present invention includes:

a pair of beads including a core and a apex located radially outside the core;

a carcass which is erected between one bead and the other bead;

a pair of fiber reinforced layers axially located outside the beads;

a pair of chafers located axially outside the fiber reinforcement layer; and

a tag structure body composed of an RFID tag and a cover rubber covering the RFID tag,

the apex has an inner apex on the core side and an outer apex on the outer side of the inner apex in the radial direction, the complex elastic modulus of the outer apex is lower than that of the inner apex, the complex elastic modulus of the chafer is higher than that of the outer apex, the carcass has at least one carcass ply having a ply body provided between one side core and the other side core, and a pair of folds connected to the ply body and folded from the inner side toward the outer side in the axial direction around the core, the tag structure is in contact with the outer apex from the outer side of the outer apex, and the ratio of the complex elastic modulus of the cover rubber to the complex elastic modulus of the outer apex is 0.7 to 1.5 between the outer end of the fiber-reinforced layer and the end of the fold in the radial direction.

Preferably, in the heavy-duty pneumatic tire, a ratio of a radial distance from an inner end of the outer apex to the RFID tag with respect to a radial height of the outer apex is 40% to 70%.

Preferably, in the heavy duty pneumatic tire, the RFID tag is located further outside than an outer end of the inner apex in a radial direction.

Preferably, the heavy-duty pneumatic tire has a pair of interlayer strips that are located inside the fiber-reinforced layer in the axial direction and cover the end portions of the folded portion. In the axial direction, the interlayer strip is located outside the RFID tag. The interlayer strip has a complex elastic modulus lower than that of the chafer and higher than that of the cap rubber.

The method for manufacturing a pneumatic tire for heavy load according to one embodiment of the present invention includes:

(1) A step of preparing a green tire having a pair of beads, a carcass provided between one bead and the other bead, a pair of fiber reinforcement layers axially located outside the beads, a pair of chafers axially located outside the fiber reinforcement layers, and a tag structure composed of an RFID tag and a cover rubber covering the RFID tag, the beads having a core, and an apex radially located outside the core, the apex having an inner apex located on the core side, and an outer apex radially located outside the inner apex, the carcass having at least one carcass ply; and

(2) A step of pressurizing and heating the green tire,

in the green tire preparing step, the label structure is attached to the outer apex, and then the carcass ply is folded around the core.

Effects of the invention

The heavy-duty pneumatic tire of the present invention realizes reduction of risk of damage to an RFID tag while taking into consideration influence on durability of a bead portion.

Drawings

Fig. 1 is a cross-sectional view showing a part of a pneumatic tire for heavy load according to an embodiment of the present invention.

Fig. 2 is an enlarged cross-sectional view showing a portion of a bead of a tire.

Fig. 3 is a cross-sectional view showing a tag structure.

Symbol description

2- & tire

4. Tread

6. Sidewall

8- & gtbead

10. Carcass

18 steel wire reinforcing layer

20 fibre reinforced layer

22/chafer

24 inter-layer strip

26 edge strip

28 label structure

38 core

40. Triangular glue

40u inner triangular glue

40s outside triangular glue

48.A carcass ply

50 DEG A ply body

52 folding part

78- & RFID tag

80- & gt cover rubber

Detailed Description

The present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings as appropriate.

In the present invention, a state in which a tire is assembled to a standard rim, the internal pressure of the tire is adjusted to a standard internal pressure, and no load is applied to the tire is referred to as a standard state. In the present invention, unless otherwise mentioned, the dimensions and angles of the respective parts of the tire are measured in a standard state.

The standard rim is a rim defined in the specification according to which the tire is mounted. "standard Rim" in JATMA specification, "Design Rim" in TRA specification, and "Measuring Rim" in ETRTO specification are standard rims.

The standard internal pressure is an internal pressure specified in the specification according to which the tire is based. The "highest air pressure" in JATMA specification, "maximum value" described by "IRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES (tire load limitation at various cold inflation pressures)" in TRA specification, and "INFLATION PRESSURE (inflation pressure)" in ETRTO specification are standard internal pressures.

The standard load refers to a load specified in the specification according to which the tire is based. "maximum LOAD CAPACITY" in JATMA specification, "maximum value" described in "IRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES (tire LOAD limitation at various cold inflation pressures)" in TRA specification, and "LOAD CAPACITY" in ETRTO specification are standard LOADs.

Fig. 1 shows a part of a heavy-duty pneumatic tire 2 (hereinafter, simply referred to as "tire 2") according to an embodiment of the present invention. The tire 2 is mounted on a vehicle such as a truck or bus. In fig. 1, a tire 2 is mounted on a rim R (standard rim). The tire 2 shown in fig. 1 is in a standard state.

Fig. 1 shows a portion of a section of a tyre 2 along a plane containing the rotation axis of the tyre 2. In fig. 1, the left-right direction is the axial direction of the tire 2, and the up-down direction is the radial direction of the tire 2. The direction perpendicular to the paper surface of fig. 1 is the circumferential direction of the tire 2. In fig. 1, a dash-dot line CL indicates the equatorial plane of the tire 2.

The tire 2 has a tread 4, a pair of sidewalls 6, a pair of beads 8, a carcass 10, a belt 12, a pair of bead fillers 14, an innerliner 16, a pair of wire reinforcement layers 18, a pair of fiber reinforcement layers 20, a pair of chafers 22, a pair of interlayer strips 24, a pair of edge strips 26, and a label structure 28.

In fig. 1, a solid line BBL extending in the axial direction is a bead base line. The bead base line is a line defining a rim diameter (refer to JATMA or the like) of a rim R (standard rim).

In fig. 1, a symbol PC is an intersection point of the inner surface of the carcass 10 and the equatorial plane. Double arrow HC is the radial distance from the bead base line to the intersection point PC. The radial distance HC is the cross-sectional height of the carcass 10.

The tread 4, the outer surface 30 thereof, i.e. the tread surface 30, is in contact with the road surface. The tread 4 has a tread surface 30 that is in contact with the road surface. The tread 4 is made of crosslinked rubber. The tread 4 has a plurality of land portions 34 divided by grooves 32 extending continuously in the circumferential direction, that is, by the circumferential grooves 32.

Each sidewall 6 is connected to an end of the tread 4. The sidewalls 6 extend radially inward from the ends of the tread 4. The inner end 36 of the sidewall 6 is located on the side of the tire 2. The side wall 6 is made of cross-linked rubber. In this tire 2, the sidewall 6 has a complex modulus of elasticity E ^* s is preferably 2MPa to 5MPa.

In this tire 2, the complex elastic modulus E of the structural element of the tire 2 such as the sidewall 6 was measured using a viscoelasticity spectrometer under the following conditions based on the specification of JIS K6394 ^* . For this measurement, test pieces obtained by pressurizing and heating the rubber composition of each structural element were used.

Initial deformation = 10%

Amplitude = ±1%

Frequency=10 Hz

Deformation mode = telescoping

Measurement temperature=70℃

Each bead 8 is located radially inside the sidewall 6. The bead 8 has a core 38 and an apex 40.

The core 38 extends circumferentially. Although not shown, the core 38 includes a coiled steel wire. The core 38 has a generally hexagonal cross-sectional shape.

The apex 40 is located radially outward of the core 38. The apex 40 has an inner apex 40u and an outer apex 40s. The inner apex 40u and the outer apex 40s are made of crosslinked rubber.

The inner apex 40u is located on the core 38 side and extends radially outward from the core 38. The outer apex 40s is radially outward of the inner apex 40 u. The outer end 42 of the inner apex 40u is radially between the outer end 44 and the inner end 46 of the outer apex 40s.

In the cross-section shown in fig. 1, the inner apex 40u tapers radially outward. The outside apex 40s has a maximum thickness near the outer end 42 of the inside apex 40 u. The outer apex 40s tapers radially outward from the portion having the greatest thickness and radially inward from the portion having the greatest thickness. The outer end 44 of the outer apex 40s is also the outer end of the apex 40.

Complex elastic modulus E of outside apex 40s ^* b complex modulus of elasticity E of the inner triangular glue 40u ^* a is low. In other words, the outside apex 40s is soft compared to the inside apex 40 u.

In this tire 2, the complex elastic modulus E of the inner apex 40u is preferably ^* a is 60MPa to 90 MPa. Preferably, the complex elastic modulus E of the outer apex 40s ^* b is 3MPa to 6 MPa.

In fig. 1, double arrow HA is the radial distance from the bead base line to the outer end 44 of the apex 40. The radial distance HA is the radial height of the apex 40. The double arrow HU is the radial distance from the bead base line to the outer end 42 of the inner apex 40 u. The radial distance HU is the radial height of the inner apex 40 u. Double arrow HS is the radial distance from the bead base line to the inner end 46 of the outboard apex 40s.

In the tire 2, the ratio of the radial height HA of the apex 40 to the cross-sectional height HC of the carcass 10 is preferably 30% to 50%. Preferably, the ratio of the radial height HU of the inner apex 40u to the cross-sectional height HC of the carcass 10 is 15% to 35%. Preferably, the ratio of the radial distance HS from the bead base line to the inner end 46 of the outer apex 40s with respect to the cross-sectional height HC of the carcass 10 is 5% to 15%.

The carcass 10 is located inside the tread 4 and the sidewalls 6. The carcass 10 is mounted between one side bead and the other. The carcass 10 has at least one carcass ply 48. The carcass 10 of the tire 2 is made up of 1 carcass ply 48.

Although not shown, the carcass ply 48 includes a plurality of carcass cords juxtaposed. These carcass cords are covered with a topping. The carcass cord is made of steel. The carcass cords intersect the equatorial plane. In this tire, the carcass 10 has a radiation type structure. Preferably, the carcass cord forms an angle of 70 ° or more and 90 ° or less with respect to the equatorial plane.

In this tire 2, the carcass ply 48 is folded from the axially inner side toward the outer side around each core 38. The carcass ply 48 has a ply body 50 and a pair of folds 52, the ply body 50 being bridged between the one-side core 38 and the other-side core 38, the pair of folds 52 being connected to the ply body 50 and folded around the core 38 from the axially inner side toward the outer side. The end 54 of the fold 52 is radially further inboard than the outer end 42 of the inner apex 40 u.

In fig. 1, double arrow HF is the radial distance from the bead baseline to the end 54 of the fold 52. The radial distance HF is the radial height of the fold 52.

In the tire 2, the ratio of the radial height HF of the folded portion 52 to the cross-sectional height HC of the carcass 10 is preferably 10% to 30%.

The belt layer 12 is located radially inside the tread 4. The belt 12 is located radially outward of the carcass 10. The belt layer 12 is laminated to the carcass 10.

The belt layer 12 is made up of a plurality of layers 56 laminated in the radial direction. The belt layer 12 of the tire 2 is composed of 4 layers 56. In this tire 2, the number of layers 56 constituting the belt layer 12 is not particularly limited. The composition of the belt layer 12 is appropriately determined in consideration of the specifications of the tire 2.

Although not shown, each layer 56 includes a plurality of belt cords juxtaposed. Each belt cord is inclined with respect to the equatorial plane. The belt ply cord is made of steel.

In this tire 2, the second layer 56B located between the first layer 56A and the third layer 56C has the largest axial width among the 4 layers 56. The fourth layer 56D located radially outermost has the smallest axial width.

Each bead 14 is located between the belt 12 and the carcass 10 at an end of the belt 12. The bead cushion 14 is made of crosslinked rubber.

An inner liner 16 is located on the inner side of the carcass 10. The inner liner 16 constitutes the inner surface of the tire 2. The inner liner 16 is made of a crosslinked rubber excellent in air shielding property.

Each wire reinforcement layer 18 is located at a portion of the bead 8. The wire reinforcement layer 18 is folded along the carcass ply 48 around the core 38 from axially inward toward outward. In this tire 2, the carcass ply 48 is located between the wire reinforcing layer 18 and the bead 8. The wire reinforcement layer 18 is contiguous with the carcass ply 48.

Although not shown, the steel wire reinforcing layer 18 includes a plurality of parallel filling cords. In the steel wire reinforcing layer 18, the filling cord is covered with a topping. The material of the filling cord is steel.

In this tire 2, one end portion 58 (hereinafter referred to as an inner end) of the wire reinforcement layer 18 is located radially between the outer end 42 of the inner apex 40u and the core 38. The other end 60 (hereinafter referred to as the outer end) of the wire reinforcement layer 18 is located radially between the end 54 of the folded portion 52 and the core 38. As shown in fig. 1, in this tire 2, the outer end 60 of the wire reinforcement layer 18 is located further outside than the inner end 58 thereof in the radial direction.

Each fiber reinforcement layer 20 is located axially outside the bead 8. One end 62 (hereinafter referred to as an outer end) of the fiber reinforced layer 20 is located radially outside the end 54 of the folded portion 52. The outer end 62 of the fiber-reinforced layer 20 is radially located between the outer end 44 of the outer apex 40s and the outer end 42 of the inner apex 40 u. The other end 64 (hereinafter referred to as the inner end) of the fiber reinforced layer 20 is located axially outside the core 38. The carcass ply 48 and the wire reinforcement 18 are located between the fiber-reinforcement 20 and the core 38. In this tire 2, the fiber-reinforced layer 20 covers the outer end 60 of the wire-reinforced layer 18.

The fiber-reinforced layer 20 is made up of 2 plies 66 after lamination. In this tire 2, the ply 66a on the bead 8 side is referred to as an inner ply, and the ply 66b on the chafer 22 side is referred to as an outer ply. As shown in fig. 1, one end 66 (hereinafter referred to as the outer end) of the outer ply 66b is located radially further outboard than the other end 70 (hereinafter referred to as the outer end) of the inner ply 66 a. The other end 72 (hereinafter referred to as the inner end) of the inner ply 66a is located radially further outboard than the other end 74 (hereinafter referred to as the inner end) of the outer ply 66b and axially further inboard than the inner end 74 of the outer ply 66 b. The outer ply 66b projects from the outer end 70 of the inner ply 66a and the inner ply 66a projects from the inner end 74 of the outer ply 66 b. The outer end 62 of the fiber-reinforced layer is the outer end 68 of the outer ply 66b and the inner end 64 of the fiber-reinforced layer 20 is the inner end 72 of the inner ply 66 a.

Although not shown, each ply 66 includes a plurality of parallel fiber cords. In the fiber-reinforced layer 20, the fiber cords are covered with a topping. The fiber cord is made of organic fibers. The organic fiber is preferably nylon fiber. In this tire 2, the fiber cords included in the fiber reinforced layer 20 are inclined with respect to the radial direction. Preferably, the angle formed by the fiber cord with respect to the radial direction is 10 ° or more and 80 ° or less. In the fiber-reinforced layer 20 of this tire 2, the inner ply 66a overlaps the outer ply 66b such that the fiber cords contained in the inner ply 66a intersect the fiber cords contained in the outer ply 66 b.

Each chafer 22 is located axially outside the fiber reinforcement layer 20. The chafer 22 is located radially inward of the sidewall 6. The outer end 76 of the chafer 22 is radially outward of the inner end 36 of the sidewall 6. The boundary between the chafer 22 and the sidewall 6 spans between the outer end 76 of the chafer 22 and the inner end 36 of the sidewall 6. The chafer 22 is in contact with the rim R.

The chafer 22 is made of crosslinked rubber. Preferably, the complex modulus of elasticity E of the chafer 22 ^* c is 10MPa to 15 MPa.

In this tire 2, the complex elastic modulus E of the chafer 22 ^* c complex elastic modulus E of 40s compared with the outside triangular glue ^* b is high. In other words, the chafer 22 is hard compared to the outer apex 40s.

Each ply strip 24 is located between an outer apex 40s of the bead 8 and the fiber reinforcement layer 20. The interlayer strip 24 covers the end 54 of the fold 52 and the outer end 60 of the wire reinforcement layer 18. The interlayer bar 24 is made of crosslinked rubber. The complex elastic modulus e×f of the interlayer bar 24 is preferably 7MPa to 12 MPa.

In this tire 2, the interlayer stock 24 has a complex modulus of elasticity e×f that is greater than the complex modulus of elasticity E of the outer apex 40s ^* b is high. In other words, the interlayer bar 24 is hard compared to the outer apex 40s.

Each edge strip 26 is located between the outer apex 40s of the bead 8 and the interlayer strip 24. The edge strip 26 abuts a portion of the end 54 of the fold 52. As shown in fig. 1, the end 54 of the fold 52 is sandwiched between the edge strip 26 and the interlayer strip 24. The edge strip 26 is made of cross-linked rubber. The complex elastic modulus e×f of the edge strip 26 is preferably 7MPa to 12 MPa. In this tire 2, the edge strip 26 is made of the same material as that of the interlayer strip 24.

Fig. 2 shows a part of the bead 8 (hereinafter, also referred to as a bead portion B) of the tire 2 shown in fig. 1. In fig. 2, the left-right direction is not the axial direction of the tire 2, and the up-down direction is the radial direction of the tire 2. The direction perpendicular to the paper surface of fig. 2 is the circumferential direction of the tire 2.

In this tire 2, the tag structure 28 is provided on one bead portion B. The tag structure 28 may be provided on both bead portions B. In this case, the tire 2 has a pair of tag structures 28.

The tag structure 28 includes an RFID tag 78. Although not described in detail, the RFID tag 78 is a small and lightweight electronic component composed of a chip semiconductor such as a signal transmission/reception circuit, a control circuit, and a memory, and an antenna. When the RFID tag 78 receives the problem wave, it uses the problem wave as electric energy, and transmits the stored data in the memory as a response wave. The RFID tag 78 is one type of passive radio frequency identification transponder.

As shown in fig. 2, in this tire 2, the entire RFID tag 78 is covered with the cover rubber 80. The tag structure 28 is composed of an RFID tag 78 and a cover rubber 80 covering the RFID tag 78. The cover rubber 80 is made of crosslinked rubber.

In this tire 2, the tag structure 28 is in contact with the outside apex 40s from the outside of the outside apex 40s. Wherein the RFID tag 78 contained in the tag structure 28 is located radially between the outer end 62 of the fiber-reinforced layer 20 and the end 54 of the fold 52.

Fig. 3 shows the tag structure 28 of fig. 2. In fig. 3, a double arrow L indicates the length of the label structure 28. The double arrow T is the thickness of the label structure 28. In fig. 3, the left side is the inner surface side of the tire 2, and the right side is the outer surface side of the tire 2. In fig. 3, the upper side is the tread 4 side of the tire 2, and the lower side is the bead 8 side of the tire 2.

The size of the tag structure 28 is appropriately set according to the size of the RFID tag 78, but the length L of the tag structure 28 is set in a range of about 10mm to 20 mm. The thickness T of the label structure 28 is set to a range of about 2mm to 4 mm.

The tire 2 was manufactured as follows. First, a tire 2 in an unvulcanized state (hereinafter also referred to as green tire) is prepared.

In this method for manufacturing the tire 2, structural members such as the tread 4 are combined in a molding machine, not shown. At least the chafer 22, the inner liner 16, the 2 plies 66 for the fiber reinforced layer 20, the wire reinforced layer 18, the interlayer strip 24, the carcass ply 48, and the edge strip 26 are wound to form a cylindrical shaped body. The beads 8 are fitted into the cylindrical molded body.

The tag structure 28 in an unvulcanized state is prepared by sandwiching the RFID tag 78 between 2 plates made of an unvulcanized state rubber composition for covering the rubber 80. The tag structure 20 is adhered to the outer apex 40s of the bead 8.

A portion outside the core 38 is folded around the core 38, the distance between the left and right cores 38 is reduced, and the portion between the left and right cores 38 is formed in a ring shape. Thereby, the carcass ply 48 is folded around the core 38. The belt layer 12, tread 4, and the like are mounted, thereby obtaining a green tire.

The green tire prepared had the same structure as the tire 2 shown in fig. 1 except that it was not molded in the unvulcanized state. The green tire is pressurized and heated. In this method for producing the tire 2, a green tire is put into a mold of a vulcanizing machine, not shown. The tire 2 is obtained by pressurizing and heating a green tire in a mold.

The method for manufacturing the tire 2 includes:

(1) Process for preparing green tyre

(2) And pressurizing and heating the green tire.

In the green tire preparation step, the label structure 28 is attached to the outer apex 40s, and then the carcass ply 48 is folded around the core 38. Thus, the label structure 28 is disposed so as to contact the outer apex 40s from the outside of the outer apex 40s, resulting in the tire 2.

In this tire 2, the RFID tag 78 is disposed in a portion between the outer apex 40s and the fiber reinforcement layer 20, that is, a portion radially outside the end 54 of the folded portion 52. The deformation of this portion is small when a load is applied. In this tire 2, the RFID tag 78 is disposed in a portion having less deformation. In this tire 2, the RFID tag 78 is less likely to be damaged.

In this tire 2, since the fiber-reinforced layer 20 reinforces the bead portion B, deformation of the bead portion B is effectively suppressed as compared with a tire in which the fiber-reinforced layer 20 is not provided. In this tire 2, the fiber-reinforced layer 20 helps to reduce the risk of damage to the RFID tag 78.

In this tire 2, the RFID tag 78 is located radially inside the outer end 62 of the fiber reinforced layer. Since the fiber reinforcement layer 20 is located between the RFID tag 78 and the chafer 22, the chafer 22 is prevented from contacting the RFID tag 78. In this tire 2, in order to prevent damage of the RFID tag 78 caused by contact with the chafer 22, it is not necessary to use a crosslinked rubber having the same rigidity as the chafer 22 as the cover rubber 80. The tire 2 may use a soft crosslinked rubber as the cap rubber 80. The soft cover rubber 80 helps to suppress concentration of deformation on the end 54 of the folded portion 52.

In this tire 2, the outer apex 40s is softer than the chafer 22. In this tire 2, the cover rubber 80 is composed of a crosslinked rubber having substantially the same rigidity as the rigidity of the outer apex 40s softer than the chafer 22. Specifically, the complex elastic modulus E of the cover rubber 80 ^* g complex modulus of elasticity E relative to the outer apex 40s ^* b ratio (E) ^* g/E ^* b) Is 0.7 to 1.5 inclusive.

Due to the ratio (E ^* g/E ^* b) The cover rubber 80 has a suitable rigidity because it is 0.7 or more. In this tire 2, excessive deformation of the cover rubber 80 upon application of load is suppressed. The cover rubber 80 helps reduce the risk of damage to the RFID tag 78. From this point of view, the ratio (E ^* g/E ^* b) Preferably 0.8 or more, and more preferably 0.9 or more.

Due to the ratio (E ^* g/E ^* b) Since the rigidity of the cover rubber 80 can be appropriately maintained at 1.5 or less. Since the cover rubber 80 is not excessively hard, concentration of deformation on the end 54 of the folded portion 52 is suppressed. In this tire 2, the durability of the bead portion B is maintained. From this point of view, the ratio (E ^* g/E ^* b) Preferably 1.2 or less, and more preferably 1.1 or less.

In this tire 2, the influence on the durability of the bead portion B is considered and the reduction of the risk of damage of the RFID tag 78 is achieved.

In fig. 2, double arrow SA is the radial height of the outside apex 40s. The radial height SA represents the radial distance from the inner end 46 to the outer end 44 of the outer apex 40s. Double arrow ST is the radial distance from the inner end 46 of the outer apex 40s to the RFID tag 78.

In this tire 2, the ratio (ST/SA) of the radial distance ST from the inner end 46 of the outer apex 40s to the radial height SA of the RFID tag 78 with respect to the outer apex 40s is preferably 40% or more, and preferably 70% or less.

The concentration of deformation at the end 54 of the folded portion 52 is suppressed by setting the ratio (ST/SA) to 40% or more. In this tire 2, the durability of the bead portion B is maintained. From this viewpoint, the ratio (ST/SA) is more preferably 50% or more, and further preferably 53% or more.

By setting the ratio (ST/SA) to 70% or less, the RFID tag 78 is disposed at a portion of the bead portion B where deformation is small. In this tire 2, a reduction in the risk of damage to the RFID tag 78 is achieved. From this viewpoint, the ratio (ST/SA) is more preferably 68% or less, and further preferably 63% or less.

As shown in fig. 2, in this tire 2, the RFID tag 78 is located further outside than the outer end 42 of the inner apex 40u in the radial direction. In this tire 2, the inner apex 40u has the highest rigidity among the elements composed of the crosslinked rubber. In this tire 2, the RFID tag 78 is configured to be radially pulled apart from the inner apex 40u having a high rigidity. Since the RFID tag 78 is effectively disposed at the portion of the bead portion B where deformation is small, a reduction in risk of damage of the RFID tag 78 is achieved in the tire 2. From this point of view, in this tire 2, it is preferable that the RFID tag 78 is located farther to the outside than the outer end 42 of the inner apex 40u in the radial direction. In this case, from the viewpoint of achieving a reduction in the risk of damage to the RFID tag 78, the radial distance from the outer end 42 of the inner apex 40u to the RFID tag 78 is preferably 1mm or more, and more preferably 2mm or more. In addition, since the further the RFID tag 78 is from the outer end 42 of the inner apex 40u, the more the risk of damage based on the inner apex 40u can be reduced, the preferable upper limit of the radial distance is not limited.

In this tire 2, the interlayer strip 24 is located axially inside the fiber-reinforced layer 20 and covers the end 54 of the fold 52. The interlayer web 24 is axially outboard of the RFID tags 78. At the wheelIn the tire 2, the complex elastic modulus e×f of the interlayer strip 24 is higher than the complex elastic modulus E of the chafer 22 ^* c is lower than the complex elastic modulus E of the covering rubber 80 ^* g is high. In this tire 2, since the interlayer strip 24 contributes to the protection of the RFID tag 78, a reduction in the risk of damage to the RFID tag 78 is achieved. From this point of view, it is preferable that the tire 2 has a pair of interlayer strips 24, the pair of interlayer strips 24 being located axially inside the fiber-reinforced layer 20 and covering the end 54 of the folded portion 52, the interlayer strips 24 being located axially outside the RFID tag 78, the complex modulus of elasticity E x f of the interlayer strips 24 being greater than the complex modulus of elasticity E of the chafer 22 ^* c is lower than the complex elastic modulus E of the covering rubber 80 ^* g is high.

In this tire 2, from the viewpoint of achieving a reduction in the risk of damage to the RFID tag 78, the complex elastic modulus e×f of the interlayer strip 24 and the complex elastic modulus E of the chafer 22 ^* c ratio (E.f/E) ^* c) Preferably 0.6 or more, and preferably 0.9 or less. From the same point of view, the complex modulus of elasticity E x f of the interlayer bar 24 and the complex modulus of elasticity E of the cover rubber 80 ^* Ratio of g (E.f/E) ^* g) Preferably 1.9 or more, and preferably 2.2 or less.

In fig. 3, double arrow TM is the thickness of the cover rubber 80. The thickness TM is represented by the minimum thickness.

In this tire 2, the thickness TM of the cover rubber 80 is preferably 1.05mm or more from the viewpoint of ensuring insulation and reading electronic information satisfactorily. From the viewpoint of suppressing the influence on the durability of the bead portion B, the thickness TM is preferably 1.75mm or less. In particular, the thickness TM of the cover rubber 80 on the outer surface side of the tire 2 is preferably 1.05mm or more, and preferably 1.75mm or less.

As is apparent from the above description, the heavy duty pneumatic tire 2 of the present invention takes into consideration the influence on the durability of the bead portion B and achieves a reduction in the risk of damage to the RFID tag 78. According to the method of manufacturing a tire of the present invention, a heavy-duty pneumatic tire 2 is obtained in which the influence on the durability of the bead portion B is taken into consideration and the risk of damage to the RFID tag 78 is reduced.

The embodiments disclosed herein are illustrative in all respects, rather than restrictive. The technical scope of the present invention is not limited to the foregoing embodiments, but includes all modifications within the scope equivalent to the structures described in the scope of the claims.

Examples

The present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples.

Example 1

A pneumatic tire for heavy load having the structure shown in fig. 1 and having the specifications shown in table 1 below (tire size=315/80 r 22.5) was obtained.

In this example 1, the ratio of the radial distance ST from the inner end of the outer apex to the RFID tag with respect to the radial height SA of the outer apex (ST/SA) was 57%.

The RFID tag is disposed between the outer end of the fiber reinforced layer and the end of the folded portion in the radial direction. This is indicated by column "in" of the tag position of table 1.

In the label structure, the thickness TM of the cover rubber is 1.25mm.

Complex elastic modulus E of external triangular glue ^* b is 4.5MPa. Complex elastic modulus E of the cover rubber ^* g is 4.5MPa. Thus, the complex elastic modulus E of the covering rubber ^* g complex elastic modulus E of triangular glue on outer side ^* b ratio (E) ^* g/E ^* b) 1.00.

Complex elastic modulus E of chafer ^* c is 12.8MPa, and the complex elastic modulus E.f of the interlayer strip is 9.5MPa.

Examples 2 to 3 and comparative example 1

By adjusting the position of the RFID tag to change the radial distance ST, the ratio (ST/SA) was as shown in table 1 below, and tires of examples 2 to 3 and comparative example 1 were obtained in the same manner as in example 1. In comparative example 1, the RFID tag was disposed radially outside the outer end of the fiber-reinforced layer. This is indicated by column "out" of the tag positions of table 1.

Examples 4 to 5 and comparative examples 2 to 3

Changing complex elastic modulus E ^* g, ratio (E) ^* g/E ^* b) As shown in Table 2 below, tires of examples 4 to 5 and comparative examples 2 to 3 were obtained in the same manner as in example 1.

Example 6

Changing complex elastic modulus E ^* g, ratio (E) ^* g/E ^* b) As shown in table 2 below, and as shown in table 2, the complex elastic modulus e×f was the same as in example 1, to obtain a tire of example 6.

[ durability ]

The test tire was assembled on a rim (size=22.5×9.00) and filled with air, and the internal pressure of the tire was adjusted to a standard internal pressure. The tire was heated in an atmosphere of dry air adjusted to 110 ℃ for 3 days. After cooling to room temperature, the tire was mounted on a drum tester. The tire was loaded with a load of 36.77kN and was driven on a drum (radius=1.7m) at a speed of 80 km/h. The running time until the bead damage was measured. The results are shown by the indices in tables 1-2 below. The larger the number, the more excellent the durability.

[ read Performance ]

The test tire was assembled on a rim (size=22.5×9.00) and filled with air, and the internal pressure of the tire was adjusted to a standard internal pressure. Using a reading device, the reception intensity of the radio wave transmitted from the RFID tag is measured. This structure is shown by the index in the following tables 1-2. The larger the number, the more excellent the reading performance.

[ safety ]

The test tire was assembled on a rim (size=22.5×9.00) and filled with air, and the internal pressure of the tire was adjusted to a standard internal pressure. The tire was mounted on a drum tester. The tire was driven over a drum (radius=1.7m) at a speed of 80km/h with a load of 36.77kN on the tire. After traveling 10 ten thousand km, the tire was disassembled to confirm the presence or absence of damage to the RFID tag. 100 tires were evaluated, and the damage rate of the RFID tag was obtained. The reciprocal of the damage rate was calculated and used as an index of safety. The results are shown by the indices in tables 1-2 below. The greater the value, the lower the risk of damage to the RFID tag.

[ Table 1]

[ Table 2 ]

As shown in tables 1-2, the examples have good durability and the risk of damage to the RFID tag is low. The advantages of the present invention are apparent from the evaluation results.

Industrial applicability

The technique of incorporating the RFID tag described above in the bead portion is applicable to various tires.

Claims

1. A heavy-duty pneumatic tire is provided with:

a pair of beads including a core and a apex located radially outside the core;

a carcass that is bridged between one bead and the other bead;

a pair of fiber reinforced layers axially located outside the beads;

a pair of chafers located axially outside the fiber reinforcement layer; and

the apex has an inner apex on the core side and an outer apex radially outward of the inner apex,

the complex elastic modulus of the outside apex is lower than that of the inside apex,

the complex modulus of elasticity of the chafer is higher than that of the outer apex,

the carcass has at least one carcass ply,

the carcass ply has a ply body erected between one core and the other core, and a pair of folded portions connected to the ply body and folded from an axially inner side to an axially outer side around the cores,

the label structure is in contact with the outer apex from the outer side of the outer apex,

the RFID tag is located radially between the outer end of the fibre reinforced layer and the end of the fold,

the ratio of the complex elastic modulus of the cover rubber to the complex elastic modulus of the outer side apex is 0.7 to 1.5,

wherein the complex elastic modulus is measured using a viscoelastic spectrometer under the following conditions: the initial deformation was 10%, the amplitude was.+ -. 1%, the frequency was 10Hz, the deformation mode was expansion and contraction, and the measurement temperature was 70 ℃.

2. The pneumatic tire for heavy loads according to claim 1, wherein,

the ratio of the radial distance from the inner end of the outer apex to the RFID tag with respect to the radial height of the outer apex is 40% to 70%.

3. The pneumatic tire for heavy load according to claim 1 or 2, wherein,

the RFID tag is located radially further outboard than the outboard end of the inboard apex.

4. The pneumatic tire for heavy load according to claim 1 or 2, wherein,

which has a pair of interlayer strips which are located axially inside the fiber-reinforced layer and cover the ends of the folded portion,

in the axial direction, the interlayer strip is located outside the RFID tag,

the interlayer strip has a complex elastic modulus lower than that of the chafer and higher than that of the cap rubber.